This invention relates to motor control systems and, more particularly, to a braking arrangement and method for use with a universal series motor.
In such a motor, if the current passing through the armature maintaines its direction, but the field direction is reversed, a torque will be produced that will oppose the rotation. Thus, the motor can be braked by reversing the field coils. However, reversing the field coils to brake the motor posesses a number of disadvantages. It is therefor an object of this invention to brake a universal series motor without using the field coils.
To improve commutation of a universal series motor, it is common practice to shift the brushes anuglarly against the direction of rotation. This causes the production of a longitudinal component of armature reaction directed against the main field produced by the field coils. It would be desirable to be able to utilize this longitudinal component as a reverse field to provide braking torque to very quickly bring the motor to a stop.
It is therefore a primary object of this invention to provide an arrangement and method whereby the longitudinal component of the armature reaction is utilized to provide braking force for a universal series motor.